Chronic absenteeism is not surprisingly associated with lower school performance, both for the individual student and for schools where these rates are especially high. Of course, this correlation doesn't mean that being absent, by itself, is the main causal factor. One suspects that students and schools with high rates of chronic absenteeism face a lot of other issues, and that absenteeism is a symptom of those broader issues. In that sense, chronic student absenteeism is a marker for a set of problems that K-12 schools face, where the school itself can't directly do much about the underlying causes of many of those problems.